Campaigners who oppose the expansion of academic selection are “exploring the possibility of legal action” over government plans to encourage existing grammar schools to expand.

Comprehensive Future has launched a crowdfunding campaign to raise £5,000 to “challenge the threat of new annexe grammar schools”, after the government encouraged grammar schools to apply for a share of a £50 million expansion fund.

New selective schools have been banned since 1998. However, in 2015, the government granted the Weald of Kent Grammar School in Kent permission to open a new annexe on a site nearly nine miles away in Sevenoaks.

Now campaigners are worried that others will use the expansion fund to open new selective schools by the back door.

These new school sites are a “shady way” to get around “the will of Parliament”, claimed Melissa Benn, who chairs Comprehensive Future.

“If further annex schools of this kind are permitted, this will damage comprehensive schools in areas bordering grammar schools,” she added.

Campaigners are now raising money to organise local campaigns, and lobby councillors and MPs. They will also “explore all legal means” to prevent groups from using the policy to open new selective schools.

Under the terms of the selective school expansion fund, which was first announced in 2016, grammar schools wishing to apply for money must first carry out a four-week consultation. They must also endeavour to admit more disadvantaged pupils, and publish a plan explaining how they will make their intakes more inclusive.

A spokesperson for the Department for Education said: “The Weald of Kent’s annex proposal was assessed against the criteria for selective school expansions‎.‎ It’s right that all good and outstanding schools – including selective schools – should be able to expand to give parents greater choice‎.

“All applications to the expansion fund must make clear that they are a genuine expansion of an existing school and meet a range of criteria, including how they will meet demand for places and increase their intake of disadvantaged pupils.”